diff --git a/src/RabbitMQClient.cpp b/src/RabbitMQClient.cpp
index d1cdc2d..b7fd5ba 100644
--- a/src/RabbitMQClient.cpp
+++ b/src/RabbitMQClient.cpp
@@ -1,5 +1,6 @@
 #include "RabbitMQClient.h"
 #include "Utils.h"
+#include <mutex>
 #include <nlohmann/json.hpp>
 #if defined(__linux__)
 #include <sys/types.h>
@@ -275,7 +276,7 @@ void RabbitMQClient::basicConsumeImpl(Biterp::CallContext& ctx) {
 					result = tag;
 					LOGI("Consumer created " + tag);
 					{
-						std::unique_lock<std::mutex> lock(_mutex);
+						std::lock_guard<std::mutex> lock(_mutex);
 						consumers.push_back(tag);
 						consumerError.clear();
 					}
@@ -302,19 +303,19 @@ void RabbitMQClient::basicConsumeImpl(Biterp::CallContext& ctx) {
 					msgOb.headers = message.headers();
 					{
 						LOGI("Consume push message");
-						std::unique_lock<std::mutex> lock(_mutex);
+						std::lock_guard<std::mutex> lock(_mutex);
 						messageQueue.push(msgOb);
 						cvDataArrived.notify_all();
 					}
 				})
 			.onCancelled([this](const std::string &consumer){
 					LOGI("Consumer cancelled " + consumer);
-					std::unique_lock<std::mutex> lock(_mutex);
+					std::lock_guard<std::mutex> lock(_mutex);
 					consumers.erase(std::remove_if(consumers.begin(), consumers.end(), [&consumer](std::string& s){return s == consumer;}));
 				})
 			.onError([this, &result](const char* message)
 				{
-					std::unique_lock<std::mutex> lock(_mutex);
+					std::lock_guard<std::mutex> lock(_mutex);
 					consumerError = message;
 					LOGE("Consumer error: " + consumerError);
 					if (result.empty()){
@@ -328,8 +329,11 @@ void RabbitMQClient::basicConsumeImpl(Biterp::CallContext& ctx) {
 
 
 void RabbitMQClient::basicConsumeMessageImpl(Biterp::CallContext& ctx) {
-	if (consumers.empty()) {
-		throw Biterp::Error("No active consumers");
+	{
+		std::lock_guard<std::mutex> lock(_mutex);
+		if (consumers.empty()) {
+			throw Biterp::Error("No active consumers");
+		}
 	}
 	ctx.skipParam();
 	tVariant* outdata = ctx.skipParam();
@@ -339,17 +343,17 @@ void RabbitMQClient::basicConsumeMessageImpl(Biterp::CallContext& ctx) {
 	ctx.setIntResult(0, outMessageTag);
 	{
 		std::unique_lock<std::mutex> lock(_mutex);
-		if (!consumerError.empty()){
-			throw Biterp::Error(consumerError);
-		}
-		if (!cvDataArrived.wait_for(lock, std::chrono::milliseconds(timeout), [&] { return !messageQueue.empty(); })) {
-			ctx.setBoolResult(false);
-			ctx.setStringResult(u"", outdata);
-			ctx.setIntResult(0, outMessageTag); 
-			return;
-		}
-		if (messageQueue.empty()) {
-			throw Biterp::Error("Empty consume message");
+		if (messageQueue.empty()){
+			if (!consumerError.empty()){
+				throw Biterp::Error(consumerError);
+			}
+			if (!cvDataArrived.wait_for(lock, std::chrono::milliseconds(timeout), [&] { return !messageQueue.empty(); })) {
+				ctx.setBoolResult(false);
+				return;
+			}
+			if (messageQueue.empty()) {
+				throw Biterp::Error("Empty consume message");
+			}
 		}
 		lastMessage = messageQueue.front();
 		messageQueue.pop();
@@ -374,7 +378,7 @@ void RabbitMQClient::clear() {
 		connection->loop();
 	}
 	consumers.clear();
-	std::unique_lock<std::mutex> lock(_mutex);
+	std::lock_guard<std::mutex> lock(_mutex);
 	std::queue<MessageObject> empty;
 	messageQueue.swap(empty);
 	cvDataArrived.notify_all();
diff --git a/test/test_amqp.py b/test/test_amqp.py
index 8485767..8736288 100644
--- a/test/test_amqp.py
+++ b/test/test_amqp.py
@@ -84,6 +84,6 @@ def test_consume_nomsg(com):
         if not ret:
             break
     assert res
-    assert msg[0] == ''
+    assert msg[0] == None
     assert mtag[0] == 0